Pulp plow apron for paper making machine



United States Patent 3,269,892 PULP FLOW APRON FOR PAPER MAKING MACHINE William N. Bennett, Fitchburg, Mass, assignor to Fit ehburg Paper Company, Fitchburg, Mass, a corporation of Delaware Filed Aug. 2, 1963, Ser. No. 299,659 12 Claims. (Cl. 162-343) This invention relates to fluid flow and more particularly to the control of the flow of a fluid so as to provide for an intermixing thereof and of any solid matter carried thereby. It is particularly adapted in papermaking for providing a uniform fiber distribution in paper pulp stock as it flows from the headbox of a papermaking machine onto the slice leading therefrom and thereafter onto the Fourdrinier wire. In brief the intermixing of the fluid and therefore the uniform distribution is accomplished by providing a new and improved repetitive, even, pattern or conformation of the surface of the slice over which the fluid or paper stock flows; the pattern or conformation comprising a plurality of aligned rows of protuberances which are carried by and extend from a base or support. Each protuberance has an edge which extends upwardly or away from the surface of the support, with each edge having portions which are, in general, at angles with respect to each other and to the edges of adjacent protu berances. These edges break the tension of the flowing fluid and in addition cause the fluid to flow in small crossing streams uniformly across the surface of the slice while at the same time restricting the fluid flow to the area covered by the protuberances and therefore obviating the need for side plates. Thus the fluid and thereby the paper stock and fibers thereof are completely and uniformly intermixed.

In a preferred form of the invention the protuberances are in the nature of fish-like scales; each such protuberance having a rounded or curved edge and having at least a portion of its thickness tapered as it approaches the edge opposite the rounded or curved edge. The protuberances are disposed on a base or support in overlapping and staggered rows like the shingles on the roof of a house. When so disposed the leading portions of the rounded or curved edges of the protuberances face downstream, and are aligned one with the other in each row of protuberances. Each row of protuberances, in turn, rise from the upper surface of the next adjacent downstream row of protuberances and are staggered with respect thereto so that the leading portion of the rounded or curved edge of the protuberances of one row are aligned with the apices formed between the protuberances of the next adjacent row.

The conformation or pattern thus formed is an even one, that is, each protuberance is substantially like every other protuberance and they are arranged in staggered rows across the slice and for an appreciable distance lengthwise of the flow.

This conformation results in complete redistribution, in a uniform manner, of the fluid and thereby of the pulp fibers in the paper stock. As such, in paper formation less Water is needed in the headbox so that less drying is needed, a shorter wire can be used and a shorter drying apparatus or cycle is suflicient for proper paper formation.

It is therefore an object of the invention to. provide an improved surface conformation to control the flow of a fluid and especially of a fluid carrying solid matter so as to provide for a complete intermixing of the fluid and thereby of the solid matter.

A further object of the invention resides in the provision of an even pattern of scale-like forms which operate equally well for all speeds of fluid or pulp flow because of the fact that the greater the speed of the fluid or the faster of flow of the pulp, the greater is the effect of the protuberances; this effect having been found to be substantially proportional to the speed involved.

A still further object of the invention resides in the provision of a pattern or conformation of scale-like forms which restricts the flow of fluid to the area covered by such forms and thereby obviates the need of side-plates or deckles.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings, in which FIG. 1 is a view in elevation showing a headbox to which the invention is applied, parts being in section;

FIG. 2 is a view in front elevation thereof, looking in the direction of arrow 2 in FIG. 1;

FIG. 3 is an enlarged View illustrating the scale-like conformation and showing diagrammatically the effect thereof;

FIG. 4 is .a view in edge elevation, looking in the direction of arrow 4 in FIG. 3;

FIG. 5 is a diagrammatic view illustrating the flow of pulp from a conventional headbox, and

FIG. 6 is a similar view showing the flow using the present invention.

As is Well known in the papermaking art when the pulp stock flows from the headbox onto the shaker, it is difiicult to control the orientation of the fibers in the pulp and ordinarily these fibers are arranged in a more or less parallel manner so that the paper strength is greater in one direction than in the other in the finished product. The pulp flow is not uniform nor is it consistent in the direction of flow and the pulp is not sufliciently turbulated in order to provide for consistent results or any approach to a uniform distribution of fibers. Many attempts have been made to overcome this problem but none have been successful.

This invention has been illustrated as applied to a headbox having in general more or less conventional parts (see FIGS. 1 and 2). The stock flows in through a pipe 10 provided with a fitting 12 and is deposited behind a first partition 14, flowing over the top thereof as indicated at 16, thence flowing downwardly into the space between an inclined partition 17 and a vertically adjustable wall 18, the latter having a transverse triangular flow-controlling member 20 thereon. This is usually referred to as an explosion box. The pulp passes underneath the lower end of wall 18 which can be vertically adjusted in order to control this flow, and thence upwardly over a partition 21, and then onto a slice generally indicated at 22 under a lower edge 24 of a front wall 26. Slice 22 may be provided with a pair of side walls or deckles 28 between which the stock flows. A thin stock-supporting apron 30 of plastic or suitable sheet metal and, preferably flexible, extend-s forwardly from slice 23 over a wire 32 which may be conventional although shorter than usual. The plastic or metal apron 30 is provided with the conformation indicated in FIGS. 1 and 2 generally as at 34 and which terminates at an end 36 disposed over Wire 32.

Slice 22 can be raised and lowered by means of a brace 38 having a locking member 40, as indicated in dotted lines in FIG. 1 from a fully open position indicated at 42 to a closed position when slice 22 is in its uppermost position, contacting lower edge 24 of front wall 26.

Referring now to FIGS. 3 and 4, the preferred embodirnent of the conformation utilized is shown, and it will be seen that the general pattern at 34 comprises a plurality of protuberances or projections indicated by the reference numeral 44 which in effect overlap succeeding protuberances somewhat in the manner of shingles or fish Aug. 30, 1966 w. N. BENNETT PULP FLOW APRON FOR PAPER MAKING MACHINE Filed Aug. 2, 1965 4 3 5 3 5 v. .1. I l a z I I. m m:x6T;nm n :r um n fi n MHMQQ, E.- Al H/ w. ,4 r Mum M n T .n 3 6 5.0., 4 Qt m n M M Ji stock contacting surface formed thereon comprising a repetitive pattern of protuberances aligned in a plurality of overlapping rows across said member, the protuberances of each row being staggered with respect to the protuberances of the adjacent row, each protuberance including an edge generally normal to the plane of said member, said edges having portions thereof arranged at angles relative to other portions thereof and directing the stock into a series of crossing streams across said member and longitudinally of the stream of stock, each protuberance having a top surface on an incline relative to the plane of said member and gradually approaching said member in a direction upstream of the flow of stock.

10. Apparatus for the uniform intermixing of a fluid comprising a member having a surf-ace over which the fluid flows, said surface being provided with a repetitive and overlapping pattern of protuberances disposed in rows with the protuberances of each row staggered with respect to the protuberances of the next adjacent row, each protuberance providing a separate edge facing the downstream direction of flow of the fluid, each of said edges having a portion disposed generally at relative angles to the direction of flow of the fluid to direct the fluid into a series of crossing streams and thereby uniformly intermix the fluid.

11. Apparatus for the uniform distribution of the fibers in the paper pulp stock of a paper making machine comprising a member having a surface over which the stock flows, said surface being provided with a repetitive pattern of overlapping rows of protuberances, the protuberances of each row being staggered with respect to the protuber-ances of the adjacent row and each protuberance providing a separate drop-off edge facing the downstream direction of flow of the stock, each drop-off edge having portions thereof generally at relative angles to the direction of flow of the stock to direct the stock into a series of crossing streams, which uniformly distribute the fibers of the paper pulp stock, while restricting the flow of the stock to said surface thereby obviating the need for side walls or deckles.

12. Apparatus for the uniform intermixing of a fluid comprising a member having a surface over which the fluid flows, said surface being provided with a repetitive and overlapping pattern of protuberances, disposed in rows with the protuberances of each row staggered with respect to the protuberances of the next adjacent row, each protuberance providing a separate edge facing the downstream direction of flow of the fluid, each of said edges having a portion disposed generally at relative angles to the direction of flow of the fluid to direct the fluid into a series of crossing streams while restricting the flow of the fluid to the area of the surface over which the protuberances are disposed to thus uniformly intermix the fluid.

References Cited by the Examiner UNITED STATES PATENTS 780,670 1/1905 Kron 162341 933,656 9/1909 Millard 162336 2,030,538 2/ 1936 Richardson 162339 2,983,383 5/1961 Wallace et a1. 162336 FOREIGN PATENTS 370,422 3/ 1923 Germany.

DONALL H. SYLVESTER, Primary Examiner.

JOHN H. NEWSOME, Assistant Examiner. 

1. APPARATUS FOR THE UNIFORM DISTRIBUTION OF THE FIBER IN THE PAPER PULP STOCK OF A PAPER MAKING MACHINE COMPRISING A MEMBER HAVING A SURFACE OVER WHICH THE STOCK FLOWS, SAID SURFACE BEING PROVIDED WITH A REPETITIVE PATTERN OF OVERLAPPING ROWS OF PROTUBERANCES, THE PROTUBERANCES OF EACH ROW BEING STAGGERED WITH RESPECT TO THE PROTUBERANCES OF THE ADJACENT ROW AND EACH PROTUBERANCE PROVIDING A SEPARATE DROP-OFF EDGE FACING THE DOWNSTREAM 